Scombroidei

Scombroidei or Scombrales is a suborder or infraorder of the order Scombriformes or suborder Scombroidei. The suborder or infraorder includes the tunas, mackerel and snake-mackerels. Regular scombrids are observed to have large heads, eyes, and mouths. In most cases, the second dorsal fin will develop before the development of the first.
The earliest known member is the scombrid Landanichthys from the Selandian of Angola, although potential fossil teeth of Eutrichiurides are slightly older.

Taxonomy

Originally, both Scombroidei and Stromateoidei were placed under the order Perciformes, but both taxa are now lumped together into the order Scombriformes or alternatively ranked as infraorders under the suborder Scombroidei within the order Syngnathiformes. Most modern taxonomic authorities use the former treatment.
The following taxonomic classification is used by Eschmeyer's Catalog of Fishes:

Suborder Scombroidei
* Family Pomatomidae Gill, 1863
* Family Icosteidae Jordan & Gilbert, 1880
* Family Arripidae Gill, 1893
* Family Chiasmodontidae Jordan & Gilbert, 1883
* Family Scombridae Rafinesque, 1815
* Family Caristiidae Gill & Smith, 1905
* Family Bramidae Bonaparte, 1831
* Superfamily Trichiuroidea
** Family Scombrolabracidae Fowler, 1925
** Family Gempylidae Gill, 1862
** Family Trichiuridae Rafinesque, 1810

Some authors consider this treatment paraphyletic with respect to Stromateoidei.
Several extinct taxa are also known:

Suborder Scombroidei
* Genus ?†Ardiodus White, 1931
* Genus †Duplexdens Monsch, 2004
* Genus †Scombramphodon Woodward, 1901
* Genus †Sphyraenodus Agassiz, 1844
* Genus †Woodwardella Casier, 1966
* Superfamily Trichiuroidea
** Genus †Argestichthys Prokofiev, 2002
** Genus †Eutrichiurides Casier, 1944
** Genus †Macroynis Beckett, Giles, Johanson & Friedman, 2018
** Family †Euzaphlegidae Daniltshenko, 1960